Thursday, August 14, 2014

Summary: Took several more spectra trying to characterize the behavior of the detector.

New to the experiment? Scroll to the bottom for background.

Low Gain linearity
run

Bias

1100 V

Gate Wind0ow

0.5 uS

Threshold

1.5mV

Attenuation

6 dB

Data set

HBC_0005

Source

Cs 137 taped to window

Start Time

8:58 AM

Stop Time

11:02 AM

Date

2014_08_14

x-y scope V/div

1, 0.5

Shielded?

Yes

Tube

Harshaw B-

The source is taped directcly to the window of the
detector. This will give the maximum
number of particles from the source impacting the detector. The counts from these runs will be used to
determine the number of counts per second from the source.

Picture of the spectrum

This spectrum had to be patched to account for the overflow
in the 662 peak channels as can be seen above.
The patched spectrum is shown below.

The slope voltage per channel was calculated again. The results are shown below

Yesterday’s troublesome question has become even stranger…
maybe. The original run that had a
higher count on the K line was done at the same bias. The only difference is that there was no
shielding present. Consequenlty, we have
from the 12th with no shielding:

Notice that the K line is almost as tall as the 662 keV
line. On the 13th, with
shielding we have:

Here’s another hint.
On the 12th, the source was not taped to the window. This should account for the difference in
counts in the 662 keV peak shown below for the shielded run on the 13th

There are several things to take note of in the above. First, the counts for the source are
increased. This would be expected
because of the source placement as mentioned above. Second, notice that the plateau signal isn’t
reduced by much. This is an indicator
that its noise, as suspected. We still
don’t have an answer for why the k line count goes down relative to the 662 keV
line however.

Run from Dewar Source Distance

Bias

1400 V

Gate Wind0ow

0.5 uS

Threshold

1.5mV

Attenuation

6 dB

Data set

HBC_0005

Source

Cs 137 Placed 2 9/16” from center of window to center of source.

Start Time

1:32 PM

Stop Time

2:34 PM

Date

2014_08_14

x-y scope V/div

1, 0.5

Shielded?

Yes

Tube

Harshaw B-

Is there a different 32 keV peak here? I thought I had eliminated the pedestal, but
looking at the entire spectrum, the pedestal and what might be two peaks show
up.

Analysis of the ‘new’
32 keV peak

By blowing up the y axis on yesterday’s data, the ‘new’ peak
at near 150 on today’s data can be seen near 140. This roughly corresponds with the observed
peak at 150 today. Here’s the plot

It can be seen that neither peak gives a line equation that
correctly predicts the Compton plateau edge

Choosing a 32 keV peak

channel

Count

Voltage

channel

Count

Voltage

86

5633

32000

150

5633

32000

995

9656

662000

995

9656

662000

rise

630000

rise

630000

run

909

run

845

slope

693.0693

slope

745.5621

offset

-27604

offset

-79834.3

150 test

76356.44

150 test

32000

plateaue test

742.5

plateaue test

760.2778

Here’s the same plat as above, from the Dewar distance
source test that shows the two predicted Compton edge channels. They’re both too large.

A Co 60 run was taken in hopes of making use of the 75 keV
Pb X-ray.

Bias

1400 V

Gate Wind0ow

0.5 uS

Threshold

1.5mV

Attenuation

6 dB

Data set

HBC_0007

Source

Co 60 Taped to window

Start Time

3:07 PM

Stop Time

3:50 PM

Date

2014_08_14

x-y scope V/div

1, 0.5

Shielded?

Yes

Tube

Harshaw B-

Picture of spectrum

It’s debatable whether or not the 75 keV peak can be seen
above or not. The spectrum looks
identical to the background only spectrum.
I’m running an overnight spectrum to get a cleaner signal.

Hirsch's theory of hole superconductivity proposes a new
BCS-compatible model of Cooper pair formation when superconducting materials
phase transition from their normal to their superconducting state[1]. One
of the experimentally verifiable predictions of his theory is that when a
superconductor rapidly transitions, (quenches), back to its normal state, it
will emit x-rays, (colloquially referred to here as H-rays because it's
Hirsch's theory).

A superconductor can be rapidly transitioned back to its normal state by
placing it in a strong magnetic field.
My experiment will look for H-rays emitted by both a Pb and a YBCO superconductor
when it is quenched by a strong magnetic field.

This series of articles chronicles both the experimental lab
work and the theory work that’s going into completing the experiment.

The lab book entries in this series detail the preparation and execution of
this experiment… mostly. I also have a
few theory projects involving special relativity and quantum field theory. Occasionally, they appear in these pages.